Computer networks utilizing Ethernet protocol as described in Standards such as: ANSI/IEEE 802.3, "Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications", 1988, 1989; IEEE 802.3b, c, d, and e, 1989 Edition, "Supplements to Carrier Sense Multiple Access with Collision Detection"; ISO/IEC 8802-3, ANSI/IEEE Std 802.3, CSMA/CD "Carrier Sense Multiple Access with Collision Detection Access Method and Physical Layer Specifications"; IEEE Std 802.3u-1995, "Media Access Control (MAC) Parameters, Physical Layer, Medium Attachment Units, and Repeater for 100 Mb/s Operation, Type 100BASE-T", Clauses 21-30; and IEEE Standard 902.9, Local and Metropolitan Area Networks, IEEE Standard Specification of ISLAN15-T, are common today.
A computer network implementing the Carrier Sense Multiple Access Method with Collision Detection (CSMA/CD) method of operation utilizes collision domains. In a collision domain, the stations attached to the network will detect a collision in the event that two or more stations attempt to transmit on the network at the same time. A collision domain is limited in its spatial extent by technical factors, principally the speed at which a station can respond to detection of a collision, the speed of transmission on the attachment medium, the length of time of a minimum length message, etc.
A longstanding problem in design of computer networks is how to provide for forwarding of data packets from a first collision domain to a second collision domain. Repeaters, as described in Chapter 9 of the ANSI/IEEE Std. 802.3b, c, d, and e 1989 Edition mentioned hereinabove have been used to extend an Ethernet collision domain. Bridges, which are devices with a store and forward functionality and operative on data packets carrying the destination address of the desired destination end station, have also been used in the past to forward a data packet from a first Ethernet collision domain to a second Ethernet collision domain. Routers, also a store and forward device and operative on data packets addressed to the router, have been used to forward data packets from a first Ethernet collision domain to a second Ethernet collision domain.
Still unresolved is how to forward a data packet from a first Ethernet collision domain to a second Ethernet collision domain by a simple and cheap method.